During the manufacture and processing of synthetic fibers, the fibers undergo various heat treatments, such as hot drawings to impart yarn strength, texturing to achieve desired aesthetic and mechanical properties, and heat setting to achieve bulk or dimensional stability. Since fiber lubricants are necessary during these procedures, it is important that the finish or lubricant be stable at the elevated temperatures employed. The lubricant should be thermally stable and not fume excessively; when exposed to the heated surfaces it should not produce a char or gum but rather a fluid residue if any decomposition does occur because gummy or varnish like residues tend to accumulate on the heated surface, create a drag on the yarn and result in yarn breakage or non-uniform stretching of the fibers. It is also important that any accumulated residue be removed readily, for example with soapy water, to facilitate cleaning of the equipment. These problems are particularly evident with the conventional polyoxyalkylene lubricants.